SEM-type reviewing apparatus and a method for reviewing defects using the same

A method for reviewing defects of patterns in a large number of chips formed on each of semiconductor wafers, the method comprising:

• a cell comparison step including of
• a first acquisition step of acquiring an electron beam defect image of a low magnification by moving a stage on which the wafer is mounted in accordance with position coordinate of a review defect on the wafer obtained from an inspection apparatus, and then imaging the review defect at the low magnification by using an electron beam optical system,
• a step of previously providing a defect detection success ratio or defect detection success map due to at least the cell comparison scheme for each wafer or for each chip formed on the wafer,
• a step of selecting a review sequence of either the cell comparison scheme or a die comparison scheme on the basis of the defect detection success ratio or defect detection success map due to at least the cell comparison scheme for each wafer or for each chip formed on the wafer previously provided in the provision step,
• a step of, if the cell comparison scheme is selected in the sequence selection step, judging whether detection of the review defect is possible by executing the cell comparison scheme based on the electron beam defect image acquired from the review defect at the low magnification in the acquisition step, and
• a first calculation step of, if judgment result in the detection possibility judgment step indicates that the detection of the review defect is possible, calculating position coordinate of the detected review defect in a coordinate system of a defect-reviewing apparatus;
• a die comparison step including of
• a second acquisition step of, if the judgment result in the detection possibility judgment step indicates that the detection of the review defect is impossible, or if the die comparison scheme is selected in the sequence selection step, acquiring an electron beam reference image at a low magnification for a normal part to perform the die comparison scheme by using the electron beam optical system with moving the stage, and
• a second calculation step of detecting the review defect by performing the die comparison scheme between the electron beam defect image of the review defect at the low magnification acquired in the first acquisition step and the electron beam reference image of the low magnification acquired in the second acquisition step, and calculating the position coordinate of the detected review defect in the coordinate system of the defect-reviewing apparatus;
• and
• a defect image acquisition step of acquiring an electron beam defect images of a high magnification by imaging the review defects at the high magnification by using the electron beam optical system in accordance with the defect position coordinates calculated in the coordinate system of the defect-reviewing apparatus in the first and second calculation steps.

A SEM-type defect-reviewing apparatus, comprising:

• a cell comparator including of
• a first acquisition unit which acquires an electron beam defect image of a low magnification with moving a stage on which a wafer is mounted in accordance with position coordinate of a review defect on the wafer obtained from an inspection apparatus, and then images the review defect at the low magnification by using an electron beam optical system,
• a review sequence selector which selects a review sequence of either a cell comparison scheme or a die comparison scheme on the basis of a defect detection success ratio or defect detection success map due to at least the cell comparison scheme for each wafer or for each chip formed on the wafer,
• a detection possibility judgment unit which, if the cell comparison scheme is selected in the review sequence selector, judges whether detection of the review defect is possible by executing the selected cell comparison scheme based on the electron beam defect image acquired from the review defect at the low magnification in the first acquisition unit, and
• a first calculator which, if judgment result in the detection possibility judgment unit indicates that the detection of the review defect is possible, calculates position coordinate of the detected review defect in a coordinate system of a defect-reviewing apparatus;
• a die comparator including of
• a second acquisition unit which, if the judgment result in the detection possibility judgment unit indicates that the detection of the review defect is impossible, or if the die comparison scheme is selected in the review sequence selector, acquires an electron beam reference image at a low magnification for a normal part to perform the selected die comparison scheme by using the electron beam optical system with moving the stage, and
• a second calculator which detects the review defect by performing the selected die comparison scheme between the electron beam defect image of the review defect at the low magnification acquired in the first acquisition unit and the electron beam reference image of the low magnification acquired in the second acquisition unit, and calculates the position coordinate of the detected review defect in the coordinate system of the defect-reviewing apparatus;
• and
• a high-magnification defect image acquisition unit which acquires electron beam defect images of a high magnification by imaging the review defects at the high magnification by using the electron beam optical system in accordance with the position coordinates of the review defects calculated in the coordinate system of the defect-reviewing apparatus in the first and second calculators.

A SEM-type defect-reviewing apparatus, comprising:

• a cell comparator including of
• a first acquisition unit which acquires an electron beam defect image of a low magnification with moving a stage on which a wafer is mounted in accordance with position coordinate of a review defect on the wafer obtained from an inspection apparatus, and then images the review defect at the low magnification by using an electron beam optical system,
• a provision unit which previously provides a defect detection success ratio or defect detection success map due to at least the cell comparison scheme for each wafer or for each chip formed on the wafer,
• a review sequence selector which selects a review sequence of either the cell comparison scheme or a die comparison scheme on the basis of the defect detection success ratio or defect detection success map due to at least the cell comparison scheme for each wafer or for each chip previously provided in the provision unit,
• a detection possibility judgment unit which, if the cell comparison scheme is selected in the review sequence selector, judges whether detection of the review defect is possible by executing the cell comparison scheme based on the electron beam defect image acquired from the review defect at the low magnification, and
• a first calculator which, if judgment result in the detection possibility judgment unit indicates that the detection of the review defect is possible, calculates position coordinate of the detected review defect in a coordinate system of a defect-reviewing apparatus;
• a die comparator including of
• a second acquisition unit which, if the judgment result in the detection possibility judgment unit indicates that the detection of the review defect is impossible, or if the die comparison scheme is selected in the review sequence selector, acquires an electron beam reference image at a low magnification for a normal part to perform the die comparison scheme by using the electron beam optical system with moving the stage, and
• a second calculator which detects the review defect by performing the die comparison scheme between the electron beam defect image of the defect at the low magnification acquired in the first acquisition unit and the electron beam reference image of the low magnification acquired in the second acquisition unit, and calculates the position coordinate of the detected review defect in the coordinate system of the defect-reviewing apparatus;
• and
• a defect image acquisition unit which acquires an electron beam defect image of a high magnification by imaging the review defects at the high magnification by using the electron beam optical system in accordance with the defect position coordinates calculated in the coordinate system of the defect-reviewing apparatus in the first and second calculators.